## B(OH)2O- ion*

 H4 \ O3 / O1 = B2 \ O5 / H6
The ion charge is -1.

## Atomic Charges and Dipole Moment

O1 charge=-0.978
B2 charge= 0.811
O3 charge=-0.760
H4 charge= 0.343
O5 charge=-0.758
H6 charge= 0.341
with a dipole moment of 5.70222 Debye

## Bond Lengths:

between O1 and B2: distance=1.318 ang___ between O1 and O3: distance=2.465 ang___
between O1 and O5: distance=2.471 ang___ between B2 and O3: distance=1.454 ang___
between B2 and O5: distance=1.457 ang___ between O3 and H4: distance=0.974 ang___
between O3 and O5: distance=2.368 ang___ between O5 and H6: distance=0.974 ang___

## Bond Angles:

for O3-B2-O1: angle=125.4 deg___ for H4-O3-B2: angle=102.7 deg___
for O5-B2-O1: angle=125.7 deg___ for H6-O5-B2: angle=102.3 deg___

## Bond Orders (Mulliken):

between O1 and B2: order=1.686___ between O1 and O3: order=-0.188___
between O1 and O5: order=-0.187___ between B2 and O3: order=0.985___
between B2 and O5: order=0.980___ between O3 and H4: order=0.883___
between O3 and O5: order=-0.117___ between O5 and H6: order=0.884___

## Best Lewis Structure

The Lewis structure that is closest to your structure is determined. The hybridization of the atoms in this idealized Lewis structure is given in the table below.

### Hybridization in the Best Lewis Structure

1. A bonding orbital for O1-B2 with 1.9986 electrons
__has 77.64% O 1 character in a sp1.04 hybrid
__has 22.36% B 2 character in a sp1.59 hybrid

2. A bonding orbital for O1-B2 with 1.9595 electrons
__has 96.38% O 1 character in a p3 hybrid
__has 3.62% B 2 character in a p3 d1.81 hybrid

3. A bonding orbital for O1-B2 with 1.9982 electrons
__has 87.80% O 1 character in a p-pi orbital ( 99.90% p 0.09% d)
__has 12.20% B 2 character in a p-pi orbital ( 98.55% p 1.45% d)

4. A bonding orbital for B2-O3 with 1.9186 electrons
__has 15.08% B 2 character in a sp1.68 d0.60 hybrid
__has 84.92% O 3 character in a sp1.50 hybrid

5. A bonding orbital for B2-O5 with 1.9182 electrons
__has 15.08% B 2 character in a sp1.62 d0.59 hybrid
__has 84.92% O 5 character in a sp1.52 hybrid

6. A bonding orbital for O3-H4 with 1.9872 electrons
__has 72.93% O 3 character in a s0.71 p3 hybrid
__has 27.07% H 4 character in a s orbital

7. A bonding orbital for O5-H6 with 1.9872 electrons
__has 72.91% O 5 character in a s0.70 p3 hybrid
__has 27.09% H 6 character in a s orbital

12. A lone pair orbital for O1 with 1.9759 electrons

13. A lone pair orbital for O3 with 1.9813 electrons

14. A lone pair orbital for O3 with 1.9288 electrons
__made from a p-pi orbital ( 99.95% p)

15. A lone pair orbital for O5 with 1.9814 electrons

16. A lone pair orbital for O5 with 1.9293 electrons
__made from a p-pi orbital ( 99.95% p)

103. A antibonding orbital for O1-B2 with 0.1428 electrons
__has 3.62% O 1 character in a p3 hybrid
__has 96.38% B 2 character in a p3 d1.81 hybrid

104. A antibonding orbital for O1-B2 with 0.1320 electrons
__has 12.20% O 1 character in a p-pi orbital ( 99.90% p 0.09% d)
__has 87.80% B 2 character in a p-pi orbital ( 98.55% p 1.45% d)

-With core pairs on: O 1 B 2 O 3 O 5 -

#### Donor Acceptor Interactions in the Best Lewis Structure

The localized orbitals in your best Lewis structure can interact strongly. A filled bonding or lone pair orbital can act as a donor and an empty or filled bonding, antibonding, or lone pair orbital can act as an acceptor. These interactions can strengthen and weaken bonds. For example, a lone pair donor->antibonding acceptor orbital interaction will weaken the bond associated with the antibonding orbital. Conversly, an interaction with a bonding pair as the acceptor will strengthen the bond. Strong electron delocalization in your best Lewis structure will also show up as donor-acceptor interactions.
Interactions greater than 20 kJ/mol for bonding and lone pair orbitals are listed below.

The interaction of the second bonding donor orbital, 2, for O1-B2 with the second antibonding acceptor orbital, 103, for O1-B2 is 25.9 kJ/mol.

The interaction of the second bonding donor orbital, 2, for O1-B2 with the antibonding acceptor orbital, 105, for B2-O3 is 130. kJ/mol.

The interaction of the second bonding donor orbital, 2, for O1-B2 with the antibonding acceptor orbital, 106, for B2-O5 is 131. kJ/mol.

The interaction of bonding donor orbital, 4, for B2-O3 with the second antibonding acceptor orbital, 103, for O1-B2 is 520. kJ/mol.

The interaction of bonding donor orbital, 4, for B2-O3 with the antibonding acceptor orbital, 105, for B2-O3 is 35.1 kJ/mol.

The interaction of bonding donor orbital, 4, for B2-O3 with the antibonding acceptor orbital, 106, for B2-O5 is 166. kJ/mol.

The interaction of bonding donor orbital, 5, for B2-O5 with the second antibonding acceptor orbital, 103, for O1-B2 is 521. kJ/mol.

The interaction of bonding donor orbital, 5, for B2-O5 with the antibonding acceptor orbital, 105, for B2-O3 is 165. kJ/mol.

The interaction of bonding donor orbital, 5, for B2-O5 with the antibonding acceptor orbital, 106, for B2-O5 is 35.4 kJ/mol.

The interaction of bonding donor orbital, 6, for O3-H4 with the second antibonding acceptor orbital, 103, for O1-B2 is 51.8 kJ/mol.

The interaction of bonding donor orbital, 7, for O5-H6 with the second antibonding acceptor orbital, 103, for O1-B2 is 51.2 kJ/mol.

The interaction of lone pair donor orbital, 13, for O3 with the antibonding acceptor orbital, 102, for O1-B2 is 35.5 kJ/mol.

The interaction of the second lone pair donor orbital, 14, for O3 with the third antibonding acceptor orbital, 104, for O1-B2 is 145. kJ/mol.

The interaction of lone pair donor orbital, 15, for O5 with the antibonding acceptor orbital, 102, for O1-B2 is 33.2 kJ/mol.

The interaction of the second lone pair donor orbital, 16, for O5 with the third antibonding acceptor orbital, 104, for O1-B2 is 143. kJ/mol.

## Molecular Orbital Energies

The orbital energies are given in eV, where 1 eV=96.49 kJ/mol. Orbitals with very low energy are core 1s orbitals. More antibonding orbitals than you might expect are sometimes listed, because d orbitals are always included for heavy atoms and p orbitals are included for H atoms. Up spins are shown with a ^ and down spins are shown as v.

20 ----- 7.283
19 ----- 6.585

18 ----- 5.825 17 ----- 5.770

16 -^-v- 0.381

15 -^-v- -0.180

14 -^-v- -1.584

13 -^-v- -1.850

12 -^-v- -3.285

11 -^-v- -3.905
10 -^-v- -3.986

9 -^-v- -5.264

8 -^-v- -7.931

7 -^-v- -15.75

6 -^-v- -18.62

5 -^-v- -19.33

4 -^-v- -169.5

3 -^-v- -498.2

2 -^-v- -500.6 1 -^-v- -500.6

## Total Electronic Energy

The total electronic energy is a very large number, so by convention the units are given in atomic units, that is Hartrees (H). One Hartree is 2625.5 kJ/mol. The energy reference is for totally dissociated atoms. In other words, the reference state is a gas consisting of nuclei and electrons all at infinite distance from each other. The electronic energy includes all electric interactions and the kinetic energy of the electrons. This energy does not include translation, rotation, or vibration of the the molecule.

Total electronic energy = -252.0119896583 Hartrees

* Note that this is not the anion that is responsible for the acidic behavior of boric acid. The acidity of boric acid is the result of the reaction:
B(OH)3 + OH- -> B(OH)4-